An apparatus as well as a method are disclosed for dispensing substances, specifically powders and liquids, from a delivery device into a recipient container, particularly into a test tube while the container is resting on the load receiver of a weighing device, specifically a balance. The weighing device can weigh the container for example before and after the dispensing of the substance and/or continuously during the dispensing of the substance into the container. After the substance or substances have been dispensed into the container, the latter may be closed with a cap.
An automated laboratory system is also disclosed that includes an apparatus or works according to a method consistent with the foregoing general description.
An apparatus and method for transferring and weighing powder materials is described in U.S. Pat. No. 6,674,022 B2. A robotic handling system uses a vacuum to draw a quantity of powder from a source container into a pipette-like transfer device, then moves the transfer device to a recipient container on a balance and drops the powder into the recipient container by switching off the vacuum and/or applying a small amount of pressure to the transfer device. The delivery of powder may include several transfers of partial quantities. The weight of the container is continuously monitored to automatically terminate the powder transfer when the target weight has been reached.
An automatic gravimetric sample-processing system for radioactive substances such as plutonium is described in FR 2 610 111 A1. Arranged inside a glove box, the system includes a sampling device, a diluting device, an electronic balance, and a remote-controlled robot arm. In the normal operating cycle, the robot arm picks up an empty recipient vessel from a turntable and places it on the balance, where the tare weight of the empty vessel is determined. The sampling device takes a sample of a liquid substance to be tested and adds it to the vessel on the balance which performs another weighing to determine the weight of the substance sample. Next, the diluting device adds a diluent to the sample in the container on the balance. After the balance has weighed the diluted sample in the container, the latter is returned to the turntable which then advances the container to a stirring device.
A fill-weighing system for a pharmaceutical production line is disclosed in EP 0 408 822 A2. Empty vessels such as vials or ampoules arriving on a conveyor device are weighed on a first balance, from where they are transferred to a filling machine to be filled with a powdery or liquid product. The filled containers are transferred to a second balance to determine or verify the correct fill weight, whereupon the filled containers leave the system to proceed to further process steps down the line. A very similar fill-weighing system is also described in U.S. Pat. No. 5,038,839.
With regard to the concepts of adding an inert gas and closing the container with a cap, a method and apparatus for sealing containers with food products such as fruit juice under an inert gas atmosphere are described in WO 94/25347 A1. Before capping, the container is put in an enclosed environment where the air is removed and an inert gas is added. Consequently, any space that is not occupied by product will be filled out by the inert gas.
In spite of their merits for the specific applications that they were proposed and designed for, the aforementioned known devices fail to address certain requirements that occur especially in the field of laboratory automation. In particular, each of the aforementioned known devices for dispensing substances into containers is designed to work in a set mode and to perform a specific task but lacks the adaptability that is required for automated laboratory applications, in particular the capability to work with a laboratory robot.